NetApp NS0-093 Exam Questions

Steps to Unfail a Disk in Maintenance Mode:

When a disk is marked as 'failed,' it is added to the Failed Disk Registry and marked as unusable by the system. Unfailing a disk involves removing it from this registry and resetting its state.

Step 1: Remove the Disk from the Failed Disk Registry

Use the command: registry remove <disk> to delete the disk from the Failed Disk Registry. This clears its 'failed' status.

Step 2: Use the Disk Unfail Command

Execute the disk unfail <disk> command to reset the disk status and make it available for use.

Key Notes:

After unfailing, the disk will be treated as a spare and must be reassigned or re-added to an aggregate.

If the disk remains failed after these steps, physical hardware issues may need to be addressed.

NetApp Reference Documentation:

The 'ONTAP Maintenance Mode Guide' and 'Disk Management Guide' provide detailed instructions for handling failed disks and using the disk unfail command.

To analyze the provided panic error, the two sections of AutoSupport that are essential for investigation are:

1. HA-RASTRACE.TGZ

What it is: HA-RASTRACE.TGZ contains HA (High Availability) system trace logs. It records hardware diagnostics, error traces, and the HA system's response to hardware events. These logs are critical when analyzing hardware-related panics, including those caused by PCI errors.

Why it's relevant to the panic: In the given panic message, the NMI (Non-Maskable Interrupt) error originates from a Qlogic FC 16G adapter. HA-RASTRACE.TGZ will provide detailed diagnostics, including the error reporting from the HA interconnect and other hardware diagnostics. Specifically, it may include information about how the system detected the PCI fault and any actions taken to protect the system state.

How to analyze:

Extract the HA-RASTRACE.TGZ file from the AutoSupport bundle.

Review hardware-related trace messages for entries associated with the PCI bus or the Qlogic FC adapter.

Look for specific error codes or keywords like PCI Error, NMI, or Qlogic.

NetApp's 'AutoSupport Logs and Diagnostics Guide' highlights HA-RASTRACE.TGZ as a primary resource for debugging hardware faults.

The 'Panic Troubleshooting Guide' for ONTAP systems specifies HA-RASTRACE as a key source for identifying NMI-related errors.

2. SSRAM-LOG

What it is: SSRAM-LOG records low-level hardware error details, including PCI device register states and uncorrectable memory errors. It is particularly useful for analyzing errors originating in peripheral hardware like network or storage adapters connected via PCI.

Why it's relevant to the panic: The panic message explicitly references a PCI Error NMI caused by a Qlogic FC adapter. SSRAM-LOG captures detailed state information for PCI devices, which can help identify whether the fault originated in the adapter hardware, the PCI bus, or another related component.

How to analyze:

Extract the SSRAM-LOG from the AutoSupport bundle.

Search for PCI-related errors, including the specific error source IDs (e.g., ErrSrcID(CorrSrc(0xf00),UCorrSrc(0x18))).

Review the log entries to confirm the root cause of the NMI.

The 'Hardware Diagnostics and Troubleshooting Guide for ONTAP' lists SSRAM-LOG as a key file for debugging PCI errors.

NetApp's documentation on PCI diagnostics emphasizes the use of SSRAM-LOG for validating hardware-level faults.

In maintenance mode, the command disk show --v provides detailed information about disk ownership. This includes the current owner, previous owner, and disk health status.

How to Use:

Enter maintenance mode, and run:

disk show --v

The output will display ownership information for each disk, including its RAID group and current assignment.

Why Other Options Are Incorrect:

A . sysconfig --v:

This command provides system configuration details but does not show disk ownership.

C . aggr status:

This command shows the status of aggregates, not individual disks or their ownership.

D . storage show disk --p:

This command is not valid in maintenance mode.

NetApp 'Maintenance Mode Commands Guide' highlights disk show --v as the command to check disk ownership.

1. L1 Watchdog Reset (WDR):

Description:

L1 WDR is a hardware-initiated reset that occurs when the system detects an unrecoverable error or lockup lasting 0.5 seconds.

Key Characteristics:

It performs a hard reset, meaning the system immediately reboots without creating a core dump.

2. L2 Watchdog Reset (WDR):

Description:

L2 WDR is initiated when the system fails to recover from a critical fault after 2 seconds.

Key Characteristics:

It requests a core dump to capture the system state for diagnostic purposes before performing a reset.

Why Other Options Are Incorrect:

B . L1 WDR is initiated after 0.5 seconds from the event:

This is incorrect because L1 WDR performs a hard reset and does not initiate after 2 seconds.

C . L1 WDR performs a soft reset:

This is incorrect because L1 WDR performs a hard reset, not a soft reset.

'ONTAP Panic Analysis Guide' describes the behavior and timing of L1 and L2 WDR events.

NetApp Support documentation on system resets explains the differences between L1 and L2 watchdog resets.

FRUs on FAS9000 Supporting Replacement Without Takeover:

A (I/O Module): I/O modules can be replaced hot (without takeover) to maintain system uptime during hardware servicing.

D (NVRAM Module): NVRAM modules on FAS9000 can also be replaced without a node takeover, ensuring data integrity during replacement.

Why Other Options Are Incorrect:

B (DCPM Module): The DCPM (Data Center Power Management) module is not hot-swappable and requires a node takeover.

C (Caching Module): The caching module is integrated and typically requires a node takeover or power-down for replacement.

NetApp Reference Documentation:

Refer to the 'NetApp FAS9000 Hardware Service Guide' for supported FRU replacement procedures and operational constraints.